Wire bonding is known as a conventional technique for connecting a wiring substrate and lead terminals electrically with each other. According to this conventional technique, a wiring substrate and lead terminals are connected together through wires, but there arises the problem that an increase of size results because it is necessary to provide a wire stretching area.
For solving this problem there has been proposed a method wherein a wiring substrate and lead terminals are connected together directly through a conductive bonding material. However, in the course of mounting parts onto the wiring substrate or in a resin molding process, a stress may be imposed on the bonded portion, causing a crack or the like in the bonding portion.
As a countermeasure there has heretofore been proposed a method wherein a wiring substrate and lead terminals are connected together directly through a conductive bonding material and thereafter a reinforcing resin is applied to the connected, or bonded, portions. This method is disclosed in, for example, Japanese Patent Application Publication No. 2001-210736.
There also has been proposed a method wherein a wiring substrate and lead terminals are connected together directly through a conductive bonding material and thereafter the fixed portions of the lead terminals are reinforced using an insulating tape. This method is disclosed in, for example, Japanese Patent Application Publication No. 2001-68582.
However, as mentioned above, according to the method wherein a wiring substrate and lead terminals are directly connected together through a conductive bonding material and thereafter the connected portions are reinforced using resin or an insulating tape, it is necessary to provide a process for disposing the resin or the insulating tape, thus resulting in an increase in the number of processes in the connection between the wiring substrate and the lead terminals.